Effect of nutrients on biomass activity in degradation of sulfate laden organics

The effects of key nutrients iron (Fe), nickel (Ni), zinc (Zn), cobalt (Co), and their combinations were investigated on the total methanogenic activity (TMA) and total sulfidogenic activity (TSA) of biomass metabolizing synthetic sulfate laden organics (COD/SO42− ratio 3.5) in batch assays. In Phase I of the study, TMA and TSA were assessed twice for four feed changes in Cycle-I and Cycle-II. Nutrient combinations Fe–Co, Fe–Ni–Zn, Ni–Zn–Co and Zn have shown maximum TMA and/or TSA. Antagonistic effects of Ni on Co uptake by methane producing bacteria (MPB) and Zn uptake by sulfate reducing bacteria (SRB) were observed. In Phase II study, sustainability of effects of nutrients for best combinations was assessed in long duration study involving 10 feed changes. Assays with Fe and Co supplementation have shown maximum stimulation of MPB and SRB.